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The crystal structure of natural eakerite [Kossiakoff & Leavens (1976). Am. Mineral. 61, 956–962] has been reinvestigated, the H-atom positions determined and the hydrogen-bonding scheme elucidated. The O...O separations of the O—H...O hydrogen bonds correlate well with the frequencies of the three corresponding Raman peaks according to Libowtzky's regression curve. The Sn atom has site symmetry \overline{1}.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807002000/hb2229sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536807002000/hb2229Isup2.hkl
Contains datablock I

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](l-O) = 0.001 Å
  • R factor = 0.027
  • wR factor = 0.066
  • Data-to-parameter ratio = 33.3

checkCIF/PLATON results

No syntax errors found



Datablock: I


Alert level A PLAT432_ALERT_2_A Short Inter X...Y Contact Si2 .. O8 .. 3.09 Ang.
Alert level B PLAT432_ALERT_2_B Short Inter X...Y Contact Si3 .. O8 .. 3.27 Ang.
Alert level C PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical . ? PLAT128_ALERT_4_C Non-standard setting of Space group P21/c .... P21/a PLAT354_ALERT_3_C Short O-H Bond (0.82A) O8 - H81 ... 0.66 Ang.
Alert level G PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K
1 ALERT level A = In general: serious problem 1 ALERT level B = Potentially serious problem 3 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 2 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check

Computing details top

Data collection: APEX2 (Bruker, 1997); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XTALDRAW (Downs & Hall-Wallace, 2003); software used to prepare material for publication: SHELXTL (Bruker, 1997).

dicalcium tin dialuminosilicate dihydroxide dihydrate top
Crystal data top
Ca2SnAl2Si6O18(OH)2·2H2OZ = 2
Mr = 779.40F(000) = 764
Monoclinic, P21/aDx = 2.912 Mg m3
Hall symbol: -P 2yabMo Kα radiation, λ = 0.71073 Å
a = 15.8202 (5) Åθ = 2.8–39.8°
b = 7.6963 (3) ŵ = 2.64 mm1
c = 7.4449 (3) ÅT = 293 K
β = 101.293 (2)°Prism, colourless
V = 888.92 (6) Å30.10 × 0.09 × 0.07 mm
Data collection top
Bruker APEX2 CCD area-detector
diffractometer
5432 independent reflections
Radiation source: fine-focus sealed tube4547 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
φ and ω scansθmax = 39.8°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 2528
Tmin = 0.776, Tmax = 0.823k = 1313
24042 measured reflectionsl = 1213
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.027Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.066All H-atom parameters refined
S = 1.05 w = 1/[σ2(Fo2) + (0.0266P)2 + 0.728P]
where P = (Fo2 + 2Fc2)/3
5432 reflections(Δ/σ)max = 0.004
163 parametersΔρmax = 0.88 e Å3
0 restraintsΔρmin = 1.15 e Å3
Special details top

Experimental. The Raman measurements were obtained on Thermo Almega microRaman system with 30 s exposure time and 15 scans using a 532 nm laser.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Sn0.00000.00000.00000.00651 (3)
Ca0.300365 (19)0.31104 (4)0.00225 (4)0.00876 (5)
Si10.45531 (5)0.16988 (5)0.71316 (6)0.00629 (7)
Si20.16629 (3)0.14507 (3)0.30892 (6)0.00636 (7)
Si30.49337 (3)0.21803 (5)0.33559 (6)0.00616 (7)
Al0.27068 (3)0.02215 (6)0.68283 (6)0.00660 (8)
O10.01960 (7)0.19958 (15)0.16104 (16)0.01086 (19)
O20.50547 (8)0.01656 (15)0.72868 (18)0.0129 (2)
O30.21455 (7)0.30912 (14)0.23632 (15)0.00992 (18)
O40.12298 (7)0.02274 (14)0.14054 (17)0.00820 (17)
O50.36271 (7)0.14553 (15)0.23084 (15)0.00947 (18)
O60.44680 (7)0.33291 (15)0.16450 (15)0.00886 (18)
O70.23642 (7)0.03515 (16)0.44934 (15)0.01008 (19)
O80.31937 (8)0.00282 (18)0.1518 (2)0.0146 (2)
O90.20206 (7)0.10401 (16)0.18049 (16)0.01123 (19)
O100.43954 (7)0.22846 (17)0.49792 (15)0.0120 (2)
O110.09213 (7)0.22090 (16)0.41285 (15)0.01080 (19)
H810.316 (3)0.002 (5)0.239 (6)0.067 (15)*
H820.363 (2)0.025 (4)0.140 (4)0.029 (8)*
H90.150 (2)0.116 (5)0.204 (5)0.046 (9)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Sn0.00652 (5)0.00640 (5)0.00631 (5)0.00026 (4)0.00054 (4)0.00031 (4)
Ca0.00858 (11)0.00888 (12)0.00905 (11)0.00034 (9)0.00227 (9)0.00044 (9)
Si10.00629 (15)0.00606 (16)0.00660 (15)0.00021 (12)0.00144 (12)0.00056 (12)
Si20.00589 (15)0.00666 (16)0.00618 (15)0.00003 (12)0.00030 (12)0.00033 (12)
Si30.00625 (15)0.00615 (16)0.00606 (15)0.00018 (12)0.00114 (12)0.00105 (12)
Al0.00669 (17)0.00700 (19)0.00594 (17)0.00023 (14)0.00081 (14)0.00031 (14)
O10.0092 (4)0.0108 (5)0.0128 (5)0.0021 (4)0.0026 (4)0.0054 (4)
O20.0121 (5)0.0068 (5)0.0190 (5)0.0018 (4)0.0009 (4)0.0015 (4)
O30.0126 (5)0.0072 (4)0.0104 (4)0.0021 (4)0.0035 (4)0.0010 (3)
O40.0073 (4)0.0089 (5)0.0077 (4)0.0004 (3)0.0005 (3)0.0025 (3)
O50.0078 (4)0.0111 (5)0.0101 (4)0.0028 (3)0.0030 (3)0.0016 (4)
O60.0085 (4)0.0098 (4)0.0077 (4)0.0001 (3)0.0002 (3)0.0035 (3)
O70.0098 (4)0.0120 (5)0.0076 (4)0.0023 (4)0.0005 (3)0.0009 (3)
O80.0095 (5)0.0180 (6)0.0157 (5)0.0009 (4)0.0012 (4)0.0001 (5)
O90.0075 (4)0.0146 (5)0.0117 (5)0.0013 (4)0.0020 (4)0.0014 (4)
O100.0105 (4)0.0186 (6)0.0076 (4)0.0010 (4)0.0035 (4)0.0019 (4)
O110.0078 (4)0.0147 (5)0.0097 (4)0.0024 (4)0.0011 (3)0.0024 (4)
Geometric parameters (Å, º) top
Sn—O1i2.0096 (11)Si2—O111.6344 (12)
Sn—O12.0096 (11)Si3—O61.6060 (11)
Sn—O42.0281 (11)Si3—O101.6110 (12)
Sn—O4i2.0281 (11)Si3—O2vii1.6238 (12)
Sn—O6ii2.0653 (11)Si3—O11viii1.6251 (12)
Sn—O6iii2.0653 (11)Al—O71.7195 (12)
Ca—O62.3997 (11)Al—O9vi1.7445 (12)
Ca—O4iv2.4001 (11)Al—O3ix1.7463 (12)
Ca—O32.4097 (11)Al—O5vi1.7517 (12)
Ca—O92.4454 (12)O2—Si3vii1.6239 (12)
Ca—O8iv2.4962 (14)O3—Alx1.7464 (12)
Ca—O52.5055 (11)O3—Ca2.4096 (11)
Ca—O82.6126 (14)O7—Al1.7194 (12)
Ca—O9iv2.6203 (13)O8—Ca2.6126 (14)
Si1—O1v1.5962 (12)O8—H810.67 (5)
Si1—O5vi1.6106 (11)O8—H820.74 (3)
Si1—O21.6327 (12)O9—Caii2.6203 (13)
Si1—O101.6361 (12)O9—H90.81 (3)
Si2—O71.6080 (12)O10—Si11.6361 (12)
Si2—O41.6096 (11)O11—Si3iii1.6251 (12)
Si2—O31.6220 (12)
O1i—Sn—O1180.0O2—Si1—O10106.88 (7)
O1—Sn—O489.85 (5)O7—Si2—O4109.44 (6)
O1i—Sn—O490.15 (5)O7—Si2—O3108.44 (6)
O1—Sn—O4i90.15 (5)O4—Si2—O3110.62 (6)
O1i—Sn—O4i89.85 (5)O7—Si2—O11110.36 (6)
O4—Sn—O4i180.0O4—Si2—O11110.00 (6)
O1—Sn—O6ii89.64 (5)O3—Si2—O11107.95 (6)
O1i—Sn—O6ii90.36 (5)O6—Si3—O10109.86 (6)
O4i—Sn—O6iii84.18 (4)O6—Si3—O2vii108.78 (7)
O4—Sn—O6iii95.83 (4)O10—Si3—O2vii107.86 (7)
O1—Sn—O6iii90.36 (5)O6—Si3—O11viii112.42 (6)
O1i—Sn—O6iii89.64 (5)O10—Si3—O11viii109.44 (6)
O4i—Sn—O6ii95.82 (4)O2vii—Si3—O11viii108.35 (7)
O4—Sn—O6ii84.17 (4)O7—Al—O9vi117.37 (6)
O6—Sn—O6i180.0O7—Al—O3ix113.42 (6)
O6—Ca—O4iv69.73 (4)O9vi—Al—O3ix101.22 (6)
O6—Ca—O3105.16 (4)O7—Al—O5vi114.46 (6)
O4iv—Ca—O3136.85 (4)O9vi—Al—O5vi99.07 (6)
O6—Ca—O9140.52 (4)O3ix—Al—O5vi109.69 (6)
O4iv—Ca—O9121.16 (4)Si1xi—O1—Sn132.54 (7)
O3—Ca—O990.65 (4)Si3vii—O2—Si1148.39 (9)
O6—Ca—O8iv139.53 (4)Si2—O3—Alx130.99 (7)
O4iv—Ca—O8iv78.40 (4)Si2—O3—Ca127.91 (6)
O3—Ca—O8iv81.46 (5)Alx—O3—Ca100.79 (5)
O9—Ca—O8iv77.70 (4)Si2—O4—Sn132.17 (6)
O6—Ca—O584.96 (4)Si2—O4—Caii124.55 (6)
O4iv—Ca—O574.74 (4)Sn—O4—Caii103.28 (4)
O3—Ca—O5148.40 (4)Si1xii—O5—Alxii134.50 (7)
O9—Ca—O564.98 (4)Si1xii—O5—Ca128.43 (6)
O8iv—Ca—O5110.41 (4)Alxii—O5—Ca96.78 (5)
O6—Ca—O880.21 (4)Si3—O6—Snviii129.51 (6)
O4iv—Ca—O8141.18 (4)Si3—O6—Ca127.47 (6)
O3—Ca—O873.77 (4)Snviii—O6—Ca102.15 (4)
O9—Ca—O869.70 (4)Si2—O7—Al136.77 (8)
O8—Ca—O8iv138.27 (3)Ca—O8—Caii109.11 (5)
O5—Ca—O878.78 (4)Caii—O8—H81104 (4)
O6—Ca—O9iv78.06 (4)Ca—O8—H81114 (3)
O4iv—Ca—O9iv72.48 (4)Caii—O8—H82114 (2)
O3—Ca—O9iv64.71 (4)Ca—O8—H82104 (2)
O9—Ca—O9iv140.50 (2)H81—O8—H82111 (4)
O8iv—Ca—O9iv68.83 (4)Alxii—O9—Ca99.16 (5)
O5—Ca—O9iv146.62 (4)Alxii—O9—Caii93.27 (5)
O8—Ca—O9iv125.27 (4)Ca—O9—Caii110.47 (4)
O1v—Si1—O5vi115.38 (6)Alxii—O9—H9129 (2)
O1v—Si1—O2105.47 (7)Ca—O9—H9124 (2)
O5vi—Si1—O2109.48 (7)Caii—O9—H995 (2)
O1v—Si1—O10111.02 (7)Si3—O10—Si1136.01 (8)
O5vi—Si1—O10108.28 (6)Si3iii—O11—Si2131.70 (8)
Symmetry codes: (i) x, y, z; (ii) x+1/2, y1/2, z; (iii) x1/2, y+1/2, z; (iv) x+1/2, y+1/2, z; (v) x+1/2, y+1/2, z+1; (vi) x, y, z+1; (vii) x+1, y, z+1; (viii) x+1/2, y+1/2, z; (ix) x+1/2, y1/2, z+1; (x) x+1/2, y+1/2, z+1; (xi) x1/2, y+1/2, z1; (xii) x, y, z1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O8—H82···O2vii0.74 (3)2.14 (3)2.7415 (18)138 (3)
O8—H81···O70.66 (4)2.21 (5)2.7981 (18)150 (5)
O9—H9···O10.81 (3)2.24 (3)3.0096 (16)157 (3)
Symmetry code: (vii) x+1, y, z+1.
 

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